The northern boundary of the Palm Island Inshore reporting zone extends east from the north-west bank of the Seaforth Channel mouth, just south of Hinchinbrook Island, to the offshore boundary and includes enclosed coastal, open coastal and mid-shelf waters.
The southern boundary of the Palm Island zone extends eastward from the southern boundary of the Herbert River Basin to just east of the Palm Island Group and runs north to the Wet Tropics NRM marine region boundary at the junction with the offshore waters boundary.
The major river discharging into the Palm Island zone is the Herbert River. Several sub-catchments, including the Seymour River, also discharge into the Palm Island inshore zone.
Water quality in the Palm Island zone is affected by plumes of sediments, nutrients and pesticides from rivers discharging directly into the zone but also from the plumes of southern rivers, particularly the Burdekin River the mouth of which is approximately 180 km to the south-east.
The area includes the Palm Island group located approximately 17 km east of the mainland. The Palm Island Group includes Orpheus Island, Pelorus Island, Fantome Island, Palm Island, and Havannah Island. These islands provide fringing shallow water environments that support coral reef ecosystems and reef seagrass meadows.
The overall grade for Palm Island zone in 2021-22 remained ‘moderate’ and the score increased from 55 to 56 since the previous year.
The diagram below shows the detailed results for each indicator by year. Click on the timeslider to see data from previous years.
The water quality grade in 2021-22 for the Palm Island inshore zone remained ‘good’ and scored 68, increasing from 62 in the previous year.
Water quality grades are based on water quality guideline trigger values established for the waters of the Great Barrier Reef Marine Park that, if exceeded, identify the need for management responses. The guidelines are not targets or assessments of pollutant loads entering the marine environment. The results are derived from in-situ water samples and water quality loggers at two inshore locations.
The water clarity score of 77 increased from 71 in 2020-21 and the grade remained ‘good’. Water clarity is comprised of total suspended solids and turbidity, both graded ‘good’.
Nutrients scored 61 (‘good’) and improved from a score of 50 (‘moderate’) in 2020-21. Nutrients are comprised of oxidised nitrogen (NOx) which improved from ‘moderate’ to ‘good’, particulate nitrogen (PN) which declined from ‘moderate’ to ‘poor’, and particulate phosphorus (PP) which remained ‘good’.
The chlorophyll a score in the Palm Island zone was 65 and increased from 64 the previous year, and the grade remained ‘good’.
From 2019-20 onwards pesticide scores were not available due to the suspension of pesticide logger deployment in the Palm Island zone.
The overall score for coral condition in 2020-21 for the Palm Island inshore zone was 45 and the grade remained ‘moderate’. Coral condition in the Palm Island zone has had a ‘moderate’ grade since 2014-15.
The coral grade is comprised of the density of juvenile hard corals score of 37 (‘poor’), the macroalgae cover score of 38 (‘poor’), the coral cover score of 47 (‘moderate’), the change in coral cover score of 47 (‘moderate’), and the coral community composition score of 58 (‘moderate’).
In the Palm Island zone declines in juvenile density occurred at all sites, and macroalgae cover increased or was sustained at several sites. High sea surface temperatures and coral bleaching occurred during the 2021-22 summer months, with soft corals substantially impacted at most sites.
More information on recent changes in coral indicators and the relationships with environmental conditions are provided in the latest Marine Monitoring Program inshore coral report.
There is no current seagrass monitoring undertaken in the Palm Island Zone and consequently there is no seagrass grade available for the Report Card in the Palm Island Zone.
The fish index is currently under development and will be available in future report cards.